What is the management of a pulmonary embolism?

Management of Pulmonary Embolism

Initiate anticoagulation immediately upon suspicion of PE before diagnostic confirmation is complete, unless the patient is actively bleeding or has absolute contraindications. 1, 2

Initial Risk Stratification and Stabilization

Hemodynamic status determines the entire management pathway and mortality risk. 2

• High-risk (massive) PE is defined by sustained hypotension (systolic BP <90 mmHg), cardiogenic shock, or cardiac arrest with evidence of right ventricular dysfunction. 1, 3
• Intermediate-risk PE presents with hemodynamic stability but evidence of RV dysfunction on echocardiography or elevated cardiac biomarkers. 1
• Low-risk PE shows hemodynamic stability without RV dysfunction or myocardial injury. 1

Perform bedside echocardiography immediately in unstable patients to differentiate high-risk PE from cardiac tamponade or acute MI. 2

Anticoagulation: The Foundation of Treatment

Initiate Before Imaging Confirmation

Start anticoagulation in patients with intermediate or high clinical probability while diagnostic workup proceeds. 1, 2

High-Risk (Massive) PE

• Administer unfractionated heparin (UFH) 80 units/kg IV bolus followed by 18 units/kg/hour infusion in hemodynamically unstable patients. 1, 4
• Adjust subsequent doses using aPTT-based nomogram targeting 1.5-2.5 times control (46-70 seconds). 1, 4
• UFH is preferred over LMWH when rapid reversal may be needed or thrombolysis is anticipated. 2

Non-High-Risk PE

Low-molecular-weight heparin (LMWH) or fondaparinux is the recommended first-line anticoagulation for hemodynamically stable patients. 1, 2

• LMWH offers more predictable pharmacokinetics, simpler fixed dosing, and no laboratory monitoring requirements compared to UFH. 5, 6
• Enoxaparin 1 mg/kg subcutaneously every 12 hours is the standard regimen. 7
• Continue parenteral anticoagulation for at least 5 days and overlap with vitamin K antagonists until INR is therapeutic (2.0-3.0) for at least 2 consecutive days. 1

Special Populations Requiring UFH

Use unfractionated heparin instead of LMWH in patients with: 1

• Severe renal dysfunction (creatinine clearance <30 mL/min)
• High bleeding risk requiring potential rapid reversal
• Morbid obesity (>150 kg)

Thrombolytic Therapy

High-Risk PE: First-Line Treatment

Thrombolytic therapy is the first-line treatment for high-risk PE presenting with cardiogenic shock and/or persistent arterial hypotension. 1, 3

• Alteplase (rtPA) 100 mg IV over 2 hours via peripheral vein is the FDA-approved accelerated regimen. 1, 3
• In cardiac arrest or rapidly deteriorating patients, give 50 mg alteplase IV bolus immediately. 1, 3
• Withhold heparin during the 2-hour alteplase infusion, then resume UFH 3 hours after completion. 3

Contraindications in Context

In life-threatening massive PE, most contraindications to thrombolysis should be ignored given the high mortality without treatment. 1, 3

Absolute contraindications include: 1

• Prior hemorrhagic stroke or stroke of unknown origin at any time
• Ischemic stroke within 6 months
• Central nervous system damage, neoplasms, or structural vascular disease
• Active bleeding or known bleeding disorder

Relative contraindications (which become less relevant in life-threatening PE): 1

• Recent major surgery/trauma within 3 weeks
• Gastrointestinal bleeding within the last month
• Pregnancy or within 1 week postpartum

Intermediate-Risk PE: Selective Use

Routine thrombolysis is not recommended for intermediate-risk PE, but may be considered in selected patients after thorough assessment of bleeding risk. 1

• A recent trial showed thrombolysis reduced clinical deterioration requiring escalation of treatment, though overall mortality was unchanged. 1
• The benefit was primarily from preventing need for emergency rescue thrombolysis. 1

Thrombolysis should not be used in low-risk PE. 1

Surgical and Catheter-Based Interventions

Surgical Pulmonary Embolectomy

Surgical embolectomy is recommended when thrombolysis is absolutely contraindicated or has failed in high-risk PE. 1

Indications include: 1

• Contraindications to thrombolysis
• Failed thrombolysis with persistent shock
• Cardiac arrest requiring cardiopulmonary resuscitation
• Patent foramen ovale with intracardiac thrombi

The procedure uses normothermic cardiopulmonary bypass with direct visualization and removal of thrombus from both pulmonary arteries. 1

Catheter-Based Interventions

Catheter embolectomy or fragmentation may be considered as an alternative to surgery when thrombolysis is contraindicated or has failed. 1

• This remains a second-line option with less robust evidence than surgery. 1
• Complications include vascular injury at puncture site, cardiac perforation, and tamponade. 1

Supportive Care

Hemodynamic Support

• Vasopressors are recommended for hypotensive patients. 1
• Dobutamine and dopamine may be used in patients with low cardiac output and normal blood pressure. 1
• Aggressive fluid challenge is not recommended as it can worsen RV function by increasing wall tension. 1

Oxygenation

Administer supplemental oxygen to maintain adequate saturation in hypoxemic patients. 1

Long-Term Anticoagulation

Vitamin K antagonists (warfarin) targeting INR 2.5 (range 2.0-3.0) are standard for long-term treatment. 1, 5

Duration of therapy: 1, 5

• At least 3 months for first PE with transient reversible risk factor
• 6-12 months for first idiopathic PE
• Indefinite for recurrent PE or active cancer

For cancer-associated PE, LMWH for at least 6 months is more effective than warfarin. 1

Critical Pitfalls to Avoid

• Never delay anticoagulation waiting for imaging in intermediate/high probability patients - PE mortality is 7% within 1 week even with treatment. 2
• Do not transfer unstable patients for additional imaging - treat based on clinical grounds if cardiac arrest is imminent. 2
• Do not order D-dimer in high clinical probability patients - proceed directly to imaging. 1, 2
• Avoid intramuscular injections due to frequent hematoma formation with anticoagulation. 4
• Do not use aggressive fluid resuscitation in RV dysfunction as it worsens outcomes. 1

Outpatient Management Consideration

Selected low-risk PE patients may be considered for outpatient treatment if: 1

• Not unduly breathless
• No medical or social contraindications
• Efficient outpatient protocol in place (similar to DVT management)